Soxhlet extraction cycle

I have a trouble with soxhlet extraction cycle.
Liquid in the middle section of soxhlet appratus should returen to the bottom section of soxhlet appratus when it reaches an appropriate height. The question is :The return did not appearence in the whole cycle but the liquid level actually reached that height.

march.12.2004
Is your procedure temperature dependent for extraction,if so volume at that temperature would had been altered.Also the viscosity must be altered.I do not actually know your specific experiment but being a physical chemis i guess possible variables which might affect experimental outcopmes.